1. Field of the Invention
The present invention is generally related to a vented liquid containment device and, more particularly, to a cap that provides a vented opening while inhibiting the flow of liquid through the vented opening.
2. Description of the Prior Art
Those skilled in the art are familiar with many types of caps and lids for enclosing containers. In many applications, it is necessary to provide a means for venting the contents of the container to atmospheric pressure. The venting can serve the purpose of allowing air to flow into the container to replace decreased volume which occurs as a result of using a liquid that is stored within the container. The venting can also serve the purpose of allowing gas to flow either into or out of the container in response to temperature change which can expand or contract the contents within the container.
U.S. Pat. No. 6,196,409, which issued to Lake et al. on Mar. 6, 2001, describes a venting means and, more particularly, a container, or a cap for a container for viscous liquid products. The container or the cap comprises a venting element. The venting element allows passage of gases between the interior and exterior of the container when the pressure inside the container differs from the external ambient pressure. The container or cap further includes a control feature which controls the phase separation of the products splashed onto the membrane.
U.S. Pat. No. 4,896,789, which issued to Federspiel on Jan. 30, 1990, describes an anti-leak fuel cap liner. A vented fuel cap is adapted to be removably attached to a filler neck of a fuel tank of the type commonly employed with small internal combustion engines. The vented fuel cap comprises a generally cylindrical cap that is formed with inner threads, and is adapted to be threadedly engaged with the filler neck. A liner element is provided to fit within the cap, and is seated along the underside of the top of the cap. The liner element includes an axially inwardly-directed film-shaped diaphragm portion that includes a slit formed substantially in its center. The cap and liner element allow for bi-directional venting of the fuel tank. The inwardly-directed dome-shaped diaphragm portion of the liner element allows outside air to vent into the fuel tank at a considerably smaller pressure differential than that required to vent outwardly from the interior of the tank.
U.S. Pat. No. 5,460,285, which issued to Harding on Oct. 24, 1995, describes a pressure relief venting lid. The lid is intended for sealing an opening and providing pressure regulation of a container. The lid has a support plate attached by four angularly spaced spring assemblies to a port cover for sealing a filler opening in a manway cover for the container. The support plate overlies the port cover for fixedly supporting the spring assemblies and cover while protecting the springs and cover from impact or shock. The spring assemblies are disposed between the support plate and port cover for sealing the cover against the opening and allowing the cover to unseat from the opening to regulate the pressure within the container. The spring assemblies are offset equal distances from the center of the port cover to minimize bending moments that the cover may be subjected to. The generally circular port cover has a convex dished portion for strengthening the port cover to maintain the seal with the opening while under load.
U.S. Pat. No. 6,010,029, which issued to Wang on Jan. 4, 2000, describes a container lid assembly. The lid assembly includes a lid body having a periphery containing a liquid discharge slot and an air vent arranged diametrically opposite to each other and a center containing a passage located between the liquid discharge slot and the air vent. It also comprises a rotary cap rotatably mounted on top of the lid body and including a drive post extending downward from the bottom thereof, and extending through the passage, a control device mounted on the bottom of the lid body and secured to the drive post to rotate with it. In such a manner, the control device can be rotated by the drive post to move between a first position where the liquid discharge slot and the air vent are closed by the control device and a second position where the liquid discharge slot and the air vent are detached from and opened by the control device.
U.S. Pat. No. 4,392,584, which issued to Bauer on Jul. 12, 1983, describes a vent cap for a container accommodating hydraulic fluids. A vent cap for a container of housing which accommodates a hydraulic operating medium is described. The vent cap includes a housing type cover which has labyrinth walls. The cover is adapted to be closed by a base insert which includes a vent passage. The vent cap is adapted to be mounted on a vent opening of the container or housing. The housing type cover is rotatably mounted on the base insert.
U.S. Pat. No. 3,861,557, which issued to Tupper on Jan. 21, 1975, describes a vent cap. A cap for a fuel tank such as is used with gasoline engines for chain saws, power mowers, snowmobiles and the like, which require venting of the tank without danger of fuel leakage resulting from return flow through the vent passageway is described. The cap has a plastic body in which is molded vent apparatus including the complete vent passageway and a check relief valve that is encapsulated within the passageway.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
One of the main problems that is inherent in any vented cap for a liquid container relates to the fact that it is usually undesirable to allow the liquid itself to pass through the vent openings. The flow of liquid from within the container through the vent openings can occur in at least two ways. The most obvious is when the container is tipped over to allow the liquid to directly contact the vent opening. It can then flow out of the container through the vent opening as a result of gravity. Another way in which the liquid within the container can escape from the container through the vent opening is when the container is subjected to shock loads that can cause the liquid to violently splash within the internal cavity of the container to the degree that liquid can become airborne with sufficient energy so as to accumulate near, and within, the vent openings and eventually flow out of the container through the vent openings.
The latter problem described immediately above can occur when the container is used to hold oil on a marine vessel. If the marine vessel is traveling on rough waters, it can be subjected to sufficient shock loading to cause the oil within the container to become airborne and splash around the inside of the container with sufficient energy to contact the internal openings of the vents. This, in turn, can cause oil to seep through the openings and into the interior of the marine vessel surrounding the oil container. It would therefore be significantly beneficial if a container of this type could be adequately vented without allowing liquid to escape through the vents when the liquid is subjected to sufficient shock loads to cause it to become airborne and rise upwardly within the cavity of the container.